Groovy - List init() method

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Description

Groovy List init() method returns the items of the list excluding the last item. Original List is not affected.

Syntax

public List init()

Parameters

NA

Return Value

A list of items minus the last item.

Example - Getting items from a List of Integers excluding the last one.

Following is an example of the usage of this method −

main.groovy

def lst = [11, 12, 13, 14, 15]

// get remaining items after excluding last one
remainingItems = lst.init()
println(remainingItems)

// original list is intact
println(lst)

Output

When we run the above program, we will get the following result −

[11, 12, 13, 14]
[11, 12, 13, 14, 15]

Example - Getting items from a List of Strings excluding the last one.

Following is an example of the usage of this method −

main.groovy

def lst = ["Apple","Mango","Orange","Papaya"]

// get remaining items after excluding the last one
remainingItems = lst.init()
println(remainingItems)

// original list is intact
println(lst)

Output

When we run the above program, we will get the following result −

[Apple, Mango, Orange]
[Apple, Mango, Orange, Papaya]

Example - Getting items from a List of Objects excluding the last one.

Following is an example of the usage of this method −

main.groovy

def lst = [new Student(1, "Julie"),new Student(2, "Robert"),new Student(3, "Adam")];

// get remaining items after excluding the last one
remainingItems = lst.init()
println(remainingItems)

// original list is intact
println(lst)

class Student {
   int rollNo;
   String name;

   Student(int rollNo, String name){
      this.rollNo = rollNo;
      this.name = name;
   }

   @Override
   public boolean equals(Object obj) {
      Student s = (Student)obj;
      return this.rollNo == s.rollNo && this.name.equalsIgnoreCase(s.name);
   }
   
   @Override
   public String toString() {
      return "[ " + this.rollNo + ", " + this.name + " ]";
   }
}

Output

When we run the above program, we will get the following result −

[[ 1, Julie ], [ 2, Robert ]]
[[ 1, Julie ], [ 2, Robert ], [ 3, Adam ]]